The need for a self-contained angle setting device is well illustrated by the common requirement in machine shops of supporting a work piece at a predetermined angle for a further operation.
While there are presently angle work holding systems available for setting precise angles between two surfaces they are not generally self-contained. A common practice is to set a wanted angle with a sine bar and gauge blocks. These systems are very time consuming and require much training; they also lack the rigidity required for many machining applications, therefore requiring extra roughing cuts, and yielding poor surfaces finishes. Stability is also a problem, the tool body is subject to move especially when downward pressure is applied to the work piece, as in the case when a hole or holes are being drilled in it.
Whether for such or other uses, the requirement is for an angle setting device which enables a wide range of angular relationships between its two surfaces to be established quickly and maintained positively during use from indicia with which the device is permanently marked.